PARTHENOGENESIS. 21 



perceived by him. The other case which is also usually reckoned 

 as a proof of a Parthenogenesis, relates to the observations made 

 by Pallas* upon Psyche graminella and Fumea nitidella, to which 

 I shall hereafter pay a closer attention (p. 24). Those cases of 

 Lucina sine concubitu which are supposed to have been observed 

 in Bees and Gall-flies, are also passed over here, as I must sub- 

 sequently subject them to a separate criticism. 



If we glance once more over all the cases hitherto referred to, 

 which were supposed to give evidence of a Parthenogenesis, the 

 whole of them agree in that the soi-disant spontaneous evolution 

 of the brood was noticed accidentally and unexpectedly by the 

 observers, so that all those precautions which are necessary for 

 the attainment of a certain observation fulfilling all the require- 

 ments of science, were entirely neglected. For this reason, 

 therefore, we must doubt the correctness of the consequences 

 which the above-mentioned naturalists have derived from their 

 observations, and the more so, as we can directly oppose to these 

 observations^ others which were made from the commencement 

 with the view of obtaining a certainty with regard to the possi- 

 bility of a spontaneous development of the unfertilized eggs of 

 insects, and which, with the employment of all the necessary 

 precautions, have only furnished negative results. As evidence 

 of this I may cite the multifarious observations of Reaumur, 

 Rosel, and the Theresians, who never obtained caterpillars from 

 the eggs laid by unimpregnated female moths. Direct experi- 

 ments in rearing caterpillars from the unimpregnated eggs of 

 moths have been made by Kefersteinf, according to his own 

 statements, in which however he always came to a negative re- 

 sult. But there is an observation made by Blancard and Aude- 

 bert upon Parthenogenesis in Spiders which may even be placed 

 in opposition to the above-mentioned inadmissible observations, 

 and this shows that the Spiders also are subjected to the general 

 physiological laws in their reproduction. BlackwallJ, namely, 



* See Nova Acta Physico-medica Academics Natures Curiosorum, torn. iii. 

 1767, p. 430: " Phalsenarum biga, quarum alterius Femina artubus prorsus 

 destitute nuda atque vermiformis, alterius glabra quidem et impennis, attamen 

 pedata est, utriusque vero, sine habito cum masculis commercio, fepcunda ova 

 par it." f See Entomologische Zeitung, 1842, p. 90. 



X See Annals of Natural History, 1845, vol. xv. p. 227- 



